Nope, it would have made Pakistan aggressor in front of rest of the world powers which would have help India.
I have to disagree. On the contrary, Pakistan could have been placed in an advantageous position -
1) The world would have been alarmed and stepped in preventing India from striking back. This could have left India with a deep wound to lick.
2) The Kashmir issue would be highlighted giving Pakistan an advantage. The follow-up action that India conducted with Kashmir could be prevented.
The main reason why Pakistan did not want to escalate was economic and political. Economic because given the condition of Pakistan's economy - there could be no chance for it to sustain the war. Political because war and it's ensuing damage would mean the end of the current PM's chances of winning again. Lastly, India's belligerent position and also the world's reaction before 26th also spooked Pakistan.
However, I remain stumped why Pakistan has not attacked India more strongly on Pulwama. It was so distracted with the events of 26 and 27th that strong condemnation even now for falsely(Pakistan's position on Pulwama) attacking Pakistan is missing. Any international report on the events of 26-27 start with the Pulwama attack but does not question India's audacity to attack another nuclear power with no proof. One gets the opinion that India was entitled to attack Pakistan to punish. The lack of heavy press on Pakistan's stance has handed India higher ground to attack at will if there was ever another terror attack, worsened by equal-equal kind of reply by Pakistan on the 27th.
India would also not wanted Pakistan to escalate on the 27th because India did not want war and did not want the Kashmir issue to be internationalized. Pakistan lost a chance with a tame comeback aimed primarily to please its citizens. India may have calculated this gamble and it has come out on top because the events of the 27th are not enough to deter India from attacking again when it chooses to. Thus, India created a battlespace for conventional skirmishes that did not exist before the 26th that will put Pakistan under high pressure.
Finally, audiences on both sides can claim their victories but if one steps backs and takes a holistic view, its undeniable that India called out Pakistan's nuclear bluff and created opportunities for conventional skirmishes in the future.